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Assessment of probabilistic system effects on the reliability of timber trusses

Hansson, Martin LU and Thelandersson, Sven LU (2002) In Materials and Structures 35(253). p.573-578
Abstract
In structural engineering the system effect is known as the possibility of transversal collaboration among parallel load-bearing elements due to mechanical load sharing. The statistical system effect, related to the variation of strength within structural timber elements, is investigated in this paper. The system investigated is a roof truss of W-type. The strength variation within and between timber members is described with a statistical model based on stochastic variables representing position of weak sections and length of weak regions, strength of weak sections and strength between weak sections. With the statistical model, the cumulative distribution of a Combined Stress Index (CSI), which is a measure of the stress levels in the... (More)
In structural engineering the system effect is known as the possibility of transversal collaboration among parallel load-bearing elements due to mechanical load sharing. The statistical system effect, related to the variation of strength within structural timber elements, is investigated in this paper. The system investigated is a roof truss of W-type. The strength variation within and between timber members is described with a statistical model based on stochastic variables representing position of weak sections and length of weak regions, strength of weak sections and strength between weak sections. With the statistical model, the cumulative distribution of a Combined Stress Index (CSI), which is a measure of the stress levels in the truss, is determined with Monte Carlo simulations. The results from the simulations are used to determine the reliability level of the truss considering the effect of within member variation of the timber strength. It is shown that the load bearing capacity of a truss is increased significantly for a given reliability level, since the probability is low that sections with locally high stresses will coincide with weak sections. The increase in the estimated load bearing capacity for a W-truss is of the order 15-20% for spruce of Scandinavian origin and 30-35% for Radiata Pine. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Materials and Structures
volume
35
issue
253
pages
573 - 578
publisher
Springer
external identifiers
  • wos:000180054300009
  • scopus:0036850593
ISSN
1359-5997
DOI
10.1007/BF02483126
language
English
LU publication?
yes
id
c81494a5-a500-4039-ae12-77c053f7999f (old id 320608)
date added to LUP
2007-08-23 13:29:49
date last changed
2017-01-01 05:18:21
@article{c81494a5-a500-4039-ae12-77c053f7999f,
  abstract     = {In structural engineering the system effect is known as the possibility of transversal collaboration among parallel load-bearing elements due to mechanical load sharing. The statistical system effect, related to the variation of strength within structural timber elements, is investigated in this paper. The system investigated is a roof truss of W-type. The strength variation within and between timber members is described with a statistical model based on stochastic variables representing position of weak sections and length of weak regions, strength of weak sections and strength between weak sections. With the statistical model, the cumulative distribution of a Combined Stress Index (CSI), which is a measure of the stress levels in the truss, is determined with Monte Carlo simulations. The results from the simulations are used to determine the reliability level of the truss considering the effect of within member variation of the timber strength. It is shown that the load bearing capacity of a truss is increased significantly for a given reliability level, since the probability is low that sections with locally high stresses will coincide with weak sections. The increase in the estimated load bearing capacity for a W-truss is of the order 15-20% for spruce of Scandinavian origin and 30-35% for Radiata Pine.},
  author       = {Hansson, Martin and Thelandersson, Sven},
  issn         = {1359-5997},
  language     = {eng},
  number       = {253},
  pages        = {573--578},
  publisher    = {Springer},
  series       = {Materials and Structures},
  title        = {Assessment of probabilistic system effects on the reliability of timber trusses},
  url          = {http://dx.doi.org/10.1007/BF02483126},
  volume       = {35},
  year         = {2002},
}